/*
 * Title:        CloudSim Toolkit
 * Description:  CloudSim (Cloud Simulation) Toolkit for Modeling and Simulation of Clouds
 * Licence:      GPL - http://www.gnu.org/copyleft/gpl.html
 *
 * Copyright (c) 2009-2012, The University of Melbourne, Australia
 */

package cloudsim.power;

import cloudsim.Vm;

import java.util.ArrayList;
import java.util.List;

/**
 * An abstract VM selection policy used to select VMs from a list of migratable VMs.
 * The selection is defined by sub classes.
 * <p>
 * <br/>If you are using any algorithms, policies or workload included in the power package please cite
 * the following paper:<br/>
 * <p>
 * <ul>
 * <li><a href="http://dx.doi.org/10.1002/cpe.1867">Anton Beloglazov, and Rajkumar Buyya, "Optimal Online Deterministic Algorithms and Adaptive
 * Heuristics for Energy and Performance Efficient Dynamic Consolidation of Virtual Machines in
 * Cloud Data Centers", Concurrency and Computation: Practice and Experience (CCPE), Volume 24,
 * Issue 13, Pages: 1397-1420, John Wiley & Sons, Ltd, New York, USA, 2012</a>
 * </ul>
 *
 * @author Anton Beloglazov
 * @since CloudSim Toolkit 3.0
 */
public abstract class PowerVmSelectionPolicy {

    /**
     * Gets a VM to migrate from a given host.
     *
     * @param host the host
     * @return the vm to migrate
     */
    public abstract Vm getVmToMigrate(PowerHost host);

    /**
     * Gets the list of migratable VMs from a given host.
     *
     * @param host the host
     * @return the list of migratable VMs
     */
    protected List<PowerVm> getMigratableVms(PowerHost host) {
        List<PowerVm> migratableVms = new ArrayList<PowerVm>();
        for (PowerVm vm : host.<PowerVm>getVmList()) {
            if (!vm.isInMigration()) {
                migratableVms.add(vm);
            }
        }
        return migratableVms;
    }

}
